Method and apparatus for melt spinning of synthetic filaments

ABSTRACT

In melt spinning of synthetic filaments, a stream of gaseous fluid is withdrawn from a region adjacent the entrance to the conditioner tube so as to substantially eliminate undesired turbulence in the quench chamber.

United States Patent Van Doornewaard et a1.

[54] METHOD AND APPARATUS FOR MELT SPINNING OF SYNTHETIC FILAMENTS [72] Inventors: Hans Van Doornewaard, Greenville, SC;

Henry G. Jackson, Guayama, RR.

[73] Assignee: Phillips Fibers Corporation [22] Filed: May 21, I970 [21 App]. No.: 39,273

[52] U.S. Cl ..264/176 F, 18/8 QM, 264/234 [51] Int. Cl ..B28b 3/20 [58] Field of Search ..264/234, 176 F; 18/8 QM [56] References Cited UNITED STATES PATENTS 3,257,487 6/1966 Dulin ..264/176 F 3,264,389 8/1966 Sims ..264/176 F 3,304,163 2/1967 Holschlag ..264/176 F 3,335,210 8/1967 Vinicki ..264/176 F 3,366,721 1/1968 Burdge et al. ..264/176 F [451 July 25, 1972 3,414,646 12/1968 Pitz1 .....264/l76 F 3,447,202 6/1969 Kato ..264/176 F 3,460,200 8/1969 Faitsev et al.. .....264/l76 F 3,460,201 8/1969 Faitsev et a1 ..264/176 F 3,492,691 2/1970 Carr ..264/176 F 3,508,296 4/1970 Ono ..264/176 F 2,252,684 8/1941 Babcock ..264/176 F FOREIGN PATENTS OR APPLICATIONS 37/7903 7/1962 Japan ..264/210 F 38/12364 7/1963 Japan ..18/8 A Primary Examiner.lay H. Woo AIl0rne v-Young and Quigg 5 7] ABSTRACT In melt spinning of synthetic filaments, a stream of gaseous fluid is withdrawn from a region adjacent the entrance to the conditioner tube so as to substantially eliminate undesired turbulence in the quench chamber.

13 Claims, 3 Drawing Figures PATENTEDJuL2s I972 sum 1 or 2 FIG. 3

INVENTORS HANS VAN DOORNEWAARD H. G. JACKSON A T TO/PNEVS PATENTEBJM m2 3.679.786

SHEEI 2 OF 2 T\ F/G. 2

INVENTORS HANS VAN DOORNEWAARD H. G ACKS N BY J 0 ATTORNEYS METHOD AND APPARATUS FOR MELT SPINNING OF SYNTHETIC FILAMENTS This invention relates to a method and an apparatus for the melt spinning of synthetic filaments. Melt spinning, in general, comprises the extrusion of molten thermoplastic materials such as vinyl polymers, polyamides, polyesters, and polyolefins into separately formed filaments and the cooling of said filaments so as to promote solidification thereof by means of a stream of gas, e.g., air, directed against and/or around said filaments. The apparatus employed to cool said filaments is commonly referred to as a quench chamber or quench apparatus. Quench chambers of the type commonly in service in the prior art comprise a vertical enclosure formed by a pair of vertically extending side panels and a foraminous back panel disposed between said side panels. The front of the chamber is usually open to the atmosphere. The filaments are extruded through a spinneret positioned in a spinning 'block and are passed downwardly through the quench chamber to a collecting convergence guide at the lower end of said chamber. The quenching fluid under pressure, such as air or other inert gas, is forced through the pores in the foraminous back panel into the chamber and around the descending filaments so as to cool and harden same.

In a number of melt spinning processes, the filaments, after being gathered or collected into a yarn at the convergence guide, are passed through an opening in a slide gate and into a conditioner tube, usually positioned below the quench chamber. In the conditioner tube, the yarn is subjected to the action of a conditioning fluid. For example, in the case of hydrophilic filaments such as nylon, the conditioner fluid usually comprises steam. In the operation of such processes some conditioning fluid (steam) escapes from the conditioner tube into the quench chamber. This is undesirable since the conditioning fluid, usually at a higher temperature than the quenching fluid, creates turbulence in the quench chamber, at least at the interface between the escaped conditioning fluid and the quenching fluid. This turbulence creates vibrations in the filaments. Said vibrations travel upward through the filaments, even beyond the stick point" of the filaments, which results in the vibration of molten filament before it has hardened. Under severe conditions such vibration can actually cause sticking of the filaments. Even when the amount of escaping conditioning fluid is held to a minimum, hot thermal currents comprising air heated by the top of the conditioner tube and/or the slide gate thereon can create said vibrations. Such vibrations of molten filament, at the very least, cause the production of filaments of substandard quality, e.g., variable denier, nonuniform cross section, etc., resulting from uneven cooling of the filaments. Such irregularities, unevenness, or nonuniformity in the filaments results in a nonuniform yarn which will not dye uniformly. Du (see ASTM 1425) is the per cent mean deviation unevenness obtained on the Uster uniformity tester and is sometimes referred to in the trade as the Uster value.

The present invention provides a solution to the above problems.

Thus, an object of this invention is to provide an improved method for melt spinning of synthetic filaments. Another object of this invention is to provide an improved method for the melt spinning of synthetic filaments wherein undesired turbulence in the quench zone is essentially eliminated. Another object of the invention is to provide an improved method for the melt spinning of synthetic filaments wherein a stream of gaseous fluid containing gaseous components which cause turbulence in the quench zone are withdrawn from a region adjacent the entrance to the conditioning zone. Another object of this invention is to provide an improved apparatus for the melt spinning of synthetic fibers. Another object of this invention is to provide means for withdrawing from the quench chamber and/or a region adjacent the entrance to the conditioner tube, a stream of gaseous fluid which causes turbulence in said quench chamber. Another object of this invention is to provide an intake assembly for withdrawing a stream of gaseous fluid from the quench chamber and/or a region adjacent the entrance to the conditioner tube, in an apparatus for the melt spinning of synthetic filaments. Other aspects, objects, and advantages of the invention will be apparent to those skilled in the art in view of this disclosure.

Thus, according to the invention, there is provided, in a method for the melt spinning of synthetic filaments wherein extruded filaments are passed through a quench zone and therein subjected to the action of a gaseous quenching fluid, quenched filaments are passed from said quench zone into a conditioner zone and therein subjected to the action of a gaseous conditioning fluid, the improvement comprising: withdrawing a stream of gaseous fluid from a region adjacent the entrance to said conditioner zone.

Further according to the invention, there is provided apparatus for the melt spinning and quenching of synthetic filaments comprising, in combination: a quench chamber; a conditioner tube positioned adjacent the lower end of said quench chamber; and intake means positioned above the upper end of said conditioner tube for withdrawing gaseous fluids from a region adjacent the entrance to said conditioner tube.

Still further according to the invention, there is provided an intake assembly, useful for withdrawing gaseous fluids, comprising in combination: an inlet nozzle; a convergence guide connected to said inlet nozzle and extending beyond the inlet side of said nozzle; and a withdrawal conduit connected to said inlet nozzle at a point spaced apart from the inlet thereof.

Said stream of gaseous fluids withdrawn from a region adjacent the entrance to the conditioner tube is withdrawn by applying a gentle vacuum or aspirating force to said region. The amount of vacuum or aspirating force applied to said region can vary over a wide range, and can be any amount sufficient to withdraw the vapors or conditioning fluid escaping from the conditioner tube, and/0r eliminate rising thermal currents, but insufficient to significantly affect the normal flow of quenching gas in the quenching chamber. Thus, the amount of vacuum or aspirating force applied will be sufficient to withdraw said vapors and/or eliminate rising thermal currents, but is insufficient to create turbulence in the quenching chamber above the convergence guide or cause vibration of the filaments. The amount of vacuum or aspirating force so applied will vary with conditions being employed in the quenching chamber, the particular polymer being extruded into filaments, the denier of said filaments, and other factors. Those skilled in the art can readily determine with minimum experimentation the amount of vacuum or aspirating force to apply in any particular situation. As a guide to those skilled in the art, the amount of vacuum or aspirating force applied can be within the range of 0.5 to 2 inches of water (measured at the inlet of the intake nozzle). However, said range will vary from installation to installation and values outside said range can be used in the practice of the invention.

FIG. 1 is a side view, partly in cross section, of an improved melt spinning apparatus in accordance with the invention.

FIG. 2 is an enlarged perspective view of the intake assembly employed in the apparatus of FIG. 1.

FIG. 3 is a side view, partly in cross section, of another melt spinning apparatus in accordance with the invention.

Referring now to said drawings, wherein like reference numerals are employed to denote like elements, the invention will be more fully explained. In FIG. 1 the apparatus comprises a spinning block 10, a spinneret assembly 12 mounted in said spinning block, a pair of elongated, spaced apart, generally parallel side panels 14 (here shown to be cut away at the lower ends thereof) positioned below said spinning block, and an elongated foraminous back panel 16 extending downwardly from said spinning block between said side panels 14. A plenum chamber 18 of any suitable shape or design, is disposed behind said back panels 16 and is adapted to receive air or any other inert gaseous quenching fluid through inlets 20 for introduction through the pores of said back panel into the space or chamber defined by said side panels 14 and said back panel 16. A conditioner tube 22 is positioned adjacent the lower end of said quench chamber. Preferably, in most instances, said conditionertube will be positioned substantially as shown in the drawing, e.g., with its entrance substantially even with the lower end of the quench chamber. However, it is within the scope of the invention for the entrance to said conditioner tube to be positioned a convenient distance above the lower end of the quench chamber or a convenient distance below the lower end of the quench chamber. An intake means or assembly, denoted generally by the reference numeral 24, is positioned above the upper end of said conditioner tube for withdrawing gaseous fluids from a region adjacent the entrance to said conditioner tube 22.

Referring now to FIG. 2, said intake means or assembly 24 comprises an inlet nozzle 26, here shown to have the general shape of a box, but which can have any desired shape such as that of an open-ended tube. The inlet end of said inlet nozzle 26 is provided with a cover plate 28, having opening 30 therein, which opening is preferably covered by a screen as shown. A convergence guide means 32 is connected to said inlet nozzle and extends beyond the inlet side or end of said nozzle. Said convergence guide means comprises guide holder 34 and guide 36 attached to the front of said guide holder 34 by means of spring clip 38. Said guide 36 can comprise a bar member having two or more generally V-shaped recesses formed therein for collecting the individual filaments into a yarn in a manner well known in the art. Any suitable type of guide means can be employed in the practice of the invention. A withdrawal conduit 40 is connected to said inlet nozzle at a point spaced apart from the inlet thereof, preferably the back side of said inlet nozzle. Support means comprising a support block 42 is provided for supporting said inlet nozzle and said convergence guide. As here shown, said support block has the general shape of an inverted U. However, it is within the scope of the invention to employ a support block having any convenient shape. As shown in FIG. 2, said convergence guide means 32 is mounted on top of inlet nozzle 26 and the region from which the stream of gaseous fluid is withdrawn via inlet nozzle 26 will be located after the point at which the filaments are gathered into a yarn, i.e., between the convergence guide and the entrance to conditioner tube 22. This represents a preferred 'form of the apparatus of the invention and a preferred method for practicing the invention. However, it is within the scope of the invention to locate convergence guide means 32 between inlet nozzle 26 and support block 42. In this instance, the region from which the stream of gaseous fluid is withdrawn will be located before the point at which the filaments are gathered into a yarn, i.e., above the convergence guide.

Said means for supporting inlet nozzle 26 and convergence guide assembly 32 can further comprise a slide gate 44 adapted to be mounted on the upper end of conditioner tube 22. In practice, said slide gate 44 will be positioned inside of channel 46, here shown in dotted lines, and said slide channel can be mounted on or attached to the upper end of conditioner tube 22 in any suitable manner as by braising or welding. Said slide gate is employed for the purpose of reducing the amount of conditioning fluid which escapes from conditioner tube 22. Said slide gate is preferably adapted to cover or close the major portion of the entrance to said conditioner tube 22 and the filaments passed downwardly into said conditioner tube through the openings between the fingers of said slide gate.

As an example, and not by way of limitation, said intake nozzle 26 was approximately 2 inches long, 6 inches wide, and three-fourths inch thick. Said slide plate 44 had an overall length of approximately 8 inches. The dimensions of the remainder of the elements were generally proportional.

Referring now to FIG. 3, there is shown diagrammatically another form of apparatus in accordance with the invention. In FIG. 3 the inlet nozzle 26' comprises an open-ended tube, as shown, which is connected to withdrawal conduit 40, which in turn is connected to a vacuum pump or other aspirating means 41. While not shown in FIG. 3, it will be understood that slide gate 44 can be mounted in a suitable slide channel 46, similarly as in FIGS. 1 and 2. Also, it will be understood that, if desired, said inlet nozzle 26 can be mounted on said slide gate 44 in any suitable manner. As shown in FIG. 3, the convergence guide comprises a loop member 48 attached to a support 50 which can be mounted in any suitable manner on the upper lip flange of conditioner tube 22.

In operation, in the practice of the invention a molten thermoplastic material such as a polyamide is extruded into filaments 52 from spinneret l2. Said filaments pass downwardly through the quench chamber where they are cooled by a stream of air or other gas admitted through panel 16, and are gathered into a yarn by means of convergence guide 36 or 48. The yarn is then passed through or between the fingers of slide plate 44 and into the conditioner tube 22 wherein it is subjected to the action of a conditioning fluid such as steam. In the practice of the invention, preferably after the filaments are gathered into a yarn, a stream of gaseous fluid, comprising conditioning fluid which has escaped from conditioner tube 22, and/or hot air forming thermal currents caused by the heating of said air by the slide gate assembly on top of condi-' tioner tube 22, is withdrawn through inlet nozzle 26 or 26' by means of a vacuum or other aspirating force applied through conduit 40.

The following examples will serve to further illustrate the invention.

EXAMPLE I A series of spinning runs was carried out at two spinning positions employing apparatus embodying the essential features of the apparatus illustrated in FIG. 3. In these runs a reclaimed conventional 6-6 nylon was spun into 70/17 yarn (70 total denier l7 filaments per yarn), with and without the application of vacuum to remove steam escaping from the entrance to the conditioner tube. The vacuum applied was adjusted to be sufficient to remove the escaping steam but insufficient to create turbulence in the quench chamber above the convergence guide. The vacuum inlet nozzle was positioned below the convergence guide as illustrated in FIG. 3. Uster values were determined periodically during the runs. The results of these determinations are set forth in Table I below.

TABLE I Average Uster Values Position I Position 2 No vacuum 1.63 1.35 With vacuum 1.48 1.24

EXAMPLE II In another series of runs carried out in essentially the same manner but using conventional newly formed 6-6 nylon, average Uster values of about 1.1 were obtained when using a vacuum to remove escaping steam from the region adjacent the entrance to the conditioner tube in accordance with the invention.

While the invention has been described herein with particular reference to using steam as the conditioning fluid, the invention is not so limited. Other conditioning fluids such as inert gases including helium, argon, etc., and air can also be used.

While certain embodiments of the invention have been described for illustrative purposes, the invention is not limited thereto. Various other modifications or embodiments of the invention will be apparent to those skilled in the art in view of this disclosure. Such modifications or embodiments are within the spirit and scope of the disclosure.

We claim:

1. In a method for the melt spinning of synthetic filaments wherein extruded filaments are passed through a quench zone and therein subjected to the action of a gaseous quenching fluid, quenched filaments are passed from said quench zone into a conditioner zone and therein subjected to the action of a gaseous conditioning fluid, and wherein a gaseous fluid from the region adjacent the entrance to said conditioning zone enters said quench zone with detrimental effects on the quality of said filaments, the improvement comprising: withdrawing a stream of gaseous fluid from said region adjacent the entrance to said conditioner zone by applying a vacuum to said region.

2. A method according to claim 1 wherein: said conditioner zone is heated; thermal currents rising from said conditioner zone enter said quench zone and create turbulence therein; and gases comprising said thermal currents are contained in said withdrawn stream of gaseous fluid.

3. A method according to claim 1 wherein: said conditioning fluid comprises steam; at least a portion of said conditioning fluid escapes from said conditioner zone into said quench zone and creates turbulence therein; and said escaped conditioning fluid is contained in said withdrawn stream of gaseous fluid.

4. A method according to claim 1 wherein: said filaments are gathered into a yarn prior to leaving said quench zone; said conditioning fluid comprises steam; at least a portion of said steam escapes from said conditioner zone into said quench zone and creates turbulence therein; said region from which said stream of gaseous fluid is withdrawn is located after the point at which said filaments are gathered into said yarn; and said escaped steam is contained in said withdrawn stream.

5. Apparatus for the melt spinning and quenching of synthetic filaments comprising, in combination: a quench chamber; a conditioner tube positioned adjacent the lower end of said quench chamber; and suction means positioned above the upper end of said conditioner tube for withdrawing gaseous fluids from a region adjacent the entrance to said conditioner tube.

6. Apparatus according to claim 5 wherein: a convergence guide is positioned above the upperend of said conditioner tube; said suction means is positioned adjacent said convergence guide; and a slide gate is mounted on the upper end of said conditioner tube.

7. Apparatus according to claim 6 wherein: said suction means is positioned between said convergence guide and said slide gate.

8. Apparatus according to claim 7 wherein said suction means comprises an inlet nozzle and a withdrawal conduit connected to said inlet nozzle.

9. Apparatus according to claim 7 wherein: said suction means comprises an inlet nozzle and a withdrawal conduit connected to said inlet nozzle; said convergence guide is mounted on top of said inlet nozzle; and said inlet noule is mounted on said slide gate.

10. Apparatus according to claim 9 wherein: an inlet nozzle support means is mounted on said slide gate; said inlet nozzle is mounted on top of said support means in spaced apart relationship with said slide gate.

11. An intake assembly, useful for withdrawing gaseous fluids from a melt spinning quench chamber, comprising in combination: an inlet nozzle; a convergence guide connected to said inlet nozzle and extending beyond the inlet side of said nozzle; and a withdrawal conduit connected to said inlet nozzle at a point spaced apart from the inlet thereof.

12. An intake assembly according to claim 11 comprising, in further combination, means for supporting said inlet nozzle and said convergence guide.

13. An intake assembly according to claim 12 wherein said support means comprises: a slide gate adapted to be mounted on the upper end of a conditioner tube in an apparatus for spinning synthetic filaments; and a support block mounted on said slide gate, with said inlet nozzle and said convergence guide being mounted on said support block. 

2. A method according to claim 1 wherein: said conditioner zone is heated; thermal currents rising from said conditioner zone enter said quench zone and create turbulence therein; and gases comprising said thermal currents are contained in said withdrawn stream of gaseous fluid.
 3. A method according to claim 1 wherein: said conditioning fluid comprises steam; at least a portion of said conditioning fluid escapes from said conditioner zone into said quench zone and creates turbulence therein; and said escaped conditioning fluid is contained in said withdrawn stream of gaseous fluid.
 4. A method according to claim 1 wherein: said filaments are gathered into a yarn prior to leaving said quench zone; said conditioning fluid comprises steam; at least a portion of said steam escapes from said conditioner zone into said quench zone and creates turbulence therein; said region from which said stream of gaseous fluid is withdrawn is located after the point at which said filaments are gathered into said yarn; and said escaped steam is contained in said withdrawn stream.
 5. Apparatus for the melt spinning and quenching of synthetic filaments comprising, in combination: a quench chamber; a conditioner tube positioned adjacent the lower end of said quench chamber; and suction means positioned above the upper end of said conditioner tube for withdrawing gaseous fluids from a region adjacent the entrance to said conditioner tube.
 6. Apparatus according to claim 5 wherein: a convergence guide is positioned above the upper end of said conditioner tube; said suction means is positioned adjacent said convergence guide; anD a slide gate is mounted on the upper end of said conditioner tube.
 7. Apparatus according to claim 6 wherein: said suction means is positioned between said convergence guide and said slide gate.
 8. Apparatus according to claim 7 wherein said suction means comprises an inlet nozzle and a withdrawal conduit connected to said inlet nozzle.
 9. Apparatus according to claim 7 wherein: said suction means comprises an inlet nozzle and a withdrawal conduit connected to said inlet nozzle; said convergence guide is mounted on top of said inlet nozzle; and said inlet nozzle is mounted on said slide gate.
 10. Apparatus according to claim 9 wherein: an inlet nozzle support means is mounted on said slide gate; said inlet nozzle is mounted on top of said support means in spaced apart relationship with said slide gate.
 11. An intake assembly, useful for withdrawing gaseous fluids from a melt spinning quench chamber, comprising in combination: an inlet nozzle; a convergence guide connected to said inlet nozzle and extending beyond the inlet side of said nozzle; and a withdrawal conduit connected to said inlet nozzle at a point spaced apart from the inlet thereof.
 12. An intake assembly according to claim 11 comprising, in further combination, means for supporting said inlet nozzle and said convergence guide.
 13. An intake assembly according to claim 12 wherein said support means comprises: a slide gate adapted to be mounted on the upper end of a conditioner tube in an apparatus for spinning synthetic filaments; and a support block mounted on said slide gate, with said inlet nozzle and said convergence guide being mounted on said support block. 